Topic 10/20

Question 1

Ethene + bromine chloride

Where does hydrogen go and wehre does chlorine go and what becomes carbocation

Answer 1

Most hydrogens accepts more positive halogen (Br) which has the most hydrogens and carbon with likely other carbons becomes carbocation and that is where cl goes

Question 2

Trends in boiling point for organic compounds (7)

Answer 2

Alkane, halogenoalkane, aldehyde, ketone, amine, alcohol, carboxylic acid

Question 3

Conformational vs configurational isomer

Answer 3

Conformational rotate around sigma bond and configurational occur in alkenes or cycoalknes and break and reform bond or rearrangement of stereocenter

Question 4

Free radical substitution

Answer 4

Inition
Cl2 = 2ClR
propagation
CH4 + ClR = RCH3 + HCl
CH3R + Cl2 = CH3CL + ClR
Termination
ClR + ClR = Cl2
RCh3 + RCH3 = C2H6

Question 5

Oxidation reactions and their OA

Answer 5

Primary alcohol, potassium dichromate
- If aldehyde, distillation, if carboxylic acid, reflux

Secondary alcohol, potassium dichomate
- To ketone

Question 6

Alkyne to alkene

Answer 6

H2 and Pt

Question 7

Alkene to alcohol

Answer 7

H20 and H2SO4

Question 8

Carboxylic acid + alochol to ester

Answer 8

water

Question 9

Nucleophillic substitutiion

Answer 9

Sn1 and Sn1

Question 10

Electrophillic addition

Answer 10

Ethenes and breaking those bonds

Question 11

Electrophillic substitution

Answer 11

Nitration of benzene

Question 12

Solvents for Sn1 and Sn2

Answer 12

Polar protic and aproptic polar respectively

Question 13

Why is hydroxide a better nucleophile than water?

Answer 13

More negative vs water is netural

Question 14

Is Sn1 or Sn2 faster. Why?

Answer 14

Sn1, because only depends on concentration of one reactant

Question 15

What ion is used in electrophillic substituion

Answer 15

No2+

Question 16

Reduction reactions and their RA

Answer 16

Carboxlyic acid to primary alcohol, LiAlH4
Aldehydte to primary alcohol sodium borohydride
Ketone to secondary alcohol, sodium borohydride

Question 17

Nitrobenzne to phenylamine

Answer 17

1) Tin and concentration HCL
2) Aqueous OH and heated under reflux

Question 18

Define stereoisomer

Answer 18

Identical molecular and structural formula but different spatial arrangement of atoms

Has chiral carbon

Question 19

Trends in boiling points (molar mass, branched chain, and functional group)

Answer 19

1) Molar mass increase, boiling point because stronger LDF
2) Branched chain are more spherical so less surface contact, thus weaker IMF and lower boiling points
3) Polar groups have stronger dipole dipole so higher boiling. Also OH and NH can form hydrogen bonds, explaining why amine, alcohol, and carboxylic acid

Question 20

In which molecules are configurational isomers?

Answer 20

Alkenes and cyclic alkanes

Question 21

Distinguish polar protic and aprotic polar solvent

Answer 21

polar protic have OH or NH so form hydrogen bonds, aprotic cannot form hydrogen bonds

Question 22

Naming esters

Answer 22

Alcohol first and carboxlyic acid second (between O and ending in oate)

alcohol is on the outside

Question 23

WHat is hydrogenation and what conditions does it occur?

Answer 23

Alkene and hydrogen gas, nickel catalyst

Question 24

Reaction for combination of nitric and sulfuric acid for the nitration of benzene

Answer 24

2H2SO4 + HNO3 = NO2+ + 2HSO4- + H30+

Question 25

Formula for calculating number of optical isomers

Answer 25

2n = where n = number of chiral centres

Question 26

Which functional group is basic?

Answer 26

amine

Question 27

Reasoning behind Markovnikov’s rule

Answer 27

Formation of more stable seconday/tertiary carbocation because of inductive effect because of extra alkyl group (s)

Question 28

How to make nitrile from halogenalkane?

Answer 28

Halogenoalkane + cn- = nitrile + halogen ion

By Sn2 reaction

Question 29

Colour change of bromine in test for unsaturation?

Answer 29

brown to colourless

Question 30

Why does benzne undergo substitution more readily than addition?

Answer 30

Resonance makes carbon-carbon bonds too strong to break

Question 31

How are primary, secondary and teritary amines classified?

Answer 31

Number of alkyl groups on the nitrogen

primary - 1 group

Question 32

Heterolytic fission of chlorine

Answer 32

Electrophillic addition, and substitution for electrophillic and nucleophillic

Question 33

Drawing stereoisomers using wedge-dash notation

Answer 33

Halogen is wedge and hydrogen is dash